Nearly 70% of nodes running Bitcoin Unlimited went offline today as word emerged of a bug in the software's code.
The bug opened a vulnerability through which a certain kind of message sent to nodes could cause them to be taken offline. Nodes are responsible for validating the transactions on a blockchain, maintaining a copy of the transaction history's entire record and essentially enforcing the rules of the network through the code.
http://www.coindesk.com/code-bug-exploi ... ted-nodes/
